Smart Antenna

Antenna, also called aerial, is a kind of transducer that is used to receive and/or transmit electromagnetic waves. Explained simply, a transducer is any object, material or structure that converts one form of energy into another. In this case, an antenna converts electrical currents to electromagnetic waves in order to transmit a signal, or vice versa while receiving. An antenna has been in use for decades and is still used today, though the usage now is very diverse.

Living in the communication age we can safely assume that almost everyone knows what an antenna is. They are the metal wire (or rod) structure sticking out on top of your TV or your car that makes the radio and the TV work. It is a medium that has made wireless communication possible, starting from the radio tuner that tells you the score of your favorite team to the very laptop you use to go around the world via internet, hail to the antenna.

Technology
Like all other tech gadgets the antenna has gone through the technology portal to make communication better. It started off as a SISO (single input single output) for radio communication. It was used only to send and receive radio signals. The shape and structure of the antenna faced a lot of changes as well. It was discovered long time back that the strength and quality of the transmitted and received signals could be changed by a great extent, just by modifying the size, shape and material. This also led to the development of two different types of antennas: Directional and Omnidirectional.

Omni Directional: Transmits and receives multi-directionally

Yagi – for radio communication

“Turnstile” type – used in commercial radio broadcasting station

Folded dipole

Cell phone

WiFi

Bluetooth

Directional: Transmits and receives in a singular direction, usually point to point with the other end.

Parabolic antenna

Satellite dish

Radar scanners

While Omni-directional antennas have the advantage of multi direction over the directional antenna, the directional antenna has proven to provide a much stronger signal with increased quality and reduced interference.

Smart Antenna
Since the birth of the antenna, it has grown until today pushing through all barriers, bringing mankind to the peak of the communication age. Then mankind says, “Why stop there? Grow some more!” and the antenna gave birth to the Smart antenna. So, exactly, how smart is it? Let’s find out!

The name may state it as an antenna but in reality it is just a system, a technique applied to radio communication that involves merging “intelligent algorithms” for signal processing into already existing antenna arrays (several antennas). The algorithms detect distinct signal signatures (spatial signatures) like the DOA (direction of arrival), and use the information to analyze the “beamforming” routes. This actually makes it possible to track and even locate a mobile target. These are actually the two main functions of the Smart antenna system: the estimation of DOA and the Beamforming.

Smart antennas are mainly used in track and scan radar, radio telescopes, radio astronomy and acoustic signal processing. This technique, surprisingly, is also commonly used in cellular systems such as the UMTS and the W-CDMA.

Types of Smart Antenna
There are many systems available today that hover around the many features of the smart antenna technology. These include phased array, spatial processing, SMDA, digital beamforming, intelligent antennas, adaptive antenna systems and many others. However, Smart antennas are usually categorized as either adaptive array systems or switched beam.

Switched Beam:
This system consists of a fixed number of predefined configurations that can be accessed or followed according to the requirement of the system. The antenna in this case simply forms a number of highly sensitive fixed beams in specific directions. However, this is achieved by combining the outputs of several antennas. This forms directional beams that are exceptionally sectorized and have an increased spatial selectivity.

Scenario: as the target (mobile) progresses through the sector its signal strength is detected by the antenna system, then selects one of the many predefined beams and shifts from the current beam to another as required.

Adaptive Array
In contrast to the Switched beam, the adaptive array consists of infinite number of configurations. This technology is by far the most technologically advanced approach of the smart antenna. It makes use of several cutting-edge signal processing algorithms to dynamically adjust itself in real time, according to requirement, in order to maximize reception signal and simultaneously reduce interference.

Although both the systems are intended to enhance “gain” respective of the user’s location, adaptive system is the only one known to provide optimum gain while identifying, tracing and reducing interference simultaneously.

This Smart Antenna Review is Written/Updated
on Mar 29th, 2010 and filed under Consumer Electronics.
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